SOC2069
Researching
Social Life 1
Quantitative data and descriptive statistics
Dr. Chris Moreh
Outline
- Variables
- Descriptive statistics
What is a variable?
- Statistical methods help us determine the factors that explain variability among subjects/respondents
- For instance, variation occurs from student to student in their grades. What factors are responsible for that variability?
- Any characteristic that we can measure for each subject is called a variable
- Variable are characteristics that can vary in value among subjects in a sample or population
- Examples of variables are income last year, number of children or siblings, whether employed, gender, how much one likes ice-cream on a scale of 1 to 10, etc.
- The values the variable can take form the measurement scale
- For gender, for instance, the measurement scale consists of the two (or more) labels, (female, male, other). For number of children/siblings, it would be (0, 1, 2, 3, 4, …)
Measurement scales
- A variable is called quantitative when the measurement scale has numerical values that represent different magnitudes of the variable
- A variable is called categorical when the measurement scale is a set of categories
- For categorical variables, distinct categories differ in quality, not in numerical magnitude. For this reason, categorical variables are often called qualitative (but we won’t call them as such, to avoid confusion with the type of qualitative data we covered in the first half of the module)
Measurement scales
Measurement scales
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The position of ordinal scales on the quantitative–qualitative classification is fuzzy. Because their scale is a set of categories, they are often analyzed using the same methods as nominal scales. But in many respects, ordinal scales more closely resemble interval scales. They possess an important quantitative feature: each level has a greater or smaller magnitude than another level
Measurement scales
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A variable’s values are discrete if its possible values form a set of separate numbers, such as (0, 1, 2, 3, . . . ).
They are continuous if it can take an infinite continuum of possible real number values.
Measurement scales
Where do variables come from?